Hello all, I'm a Guile developer who is trying to figure out the best way to add a Guile-specific 'extensions' directory to the library search path, while retaining the ability of 'libtool --mode=execute -dlopen' to take precedence over our default extensions directory.
As I understand it, on GNU systems 'libtool --mode=execute -dlopen' has the effect of prepending a directory to $LD_LIBRARY_PATH. It also appears from the libltdl source code that the search order for 'lt_dlopenext' is as follows: * user_search_path (augmented by 'lt_dladdsearchdir' et al) * LTDL_LIBRARY_PATH * LD_LIBRARY_PATH * system default search path I see only two ways to add our extensions directory to the search path, such that it can be overridden by 'libtool --mode=execute -dlopen': 1. Append it to LD_LIBRARY_PATH. 2. Search in our extensions directory manually if 'lt_dlopenext' fails, by calling 'lt_dlopenext' a second time. The problem with option 1 is that all subprocesses will inherit our modified search path. This could be a problem if there are two different versions of Guile on the system, and one is used by a subprocess of the other, because the sub-Guile will search in the parent-Guile's extensions directory first. Therefore, it seems that option 2 is the right thing, even though it is quite kludgy. I can't help but suspect that 'lt_dladdsearchdir' et al were intended for programs to add their own system-wide extensions directory to the search path. Is that right? If so, what's the recommended way to override a program's default extensions directory? Maybe the problem is that programs should not expect 'libtool --mode=execute -dlopen' to override a program's extension directory. However, it is being used this way in practice, for example by GNU TLS (which provides a Guile extension) to ask that the uninstalled extension in its build directory should take precedence over the one in the system-wide Guile extensions directory. See <http://git.savannah.gnu.org/cgit/gnutls.git/tree/guile/pre-inst-guile.in>. I'm hoping that the libtool experts here can help me understand how this is supposed to work. I'm not subscribed to this list, so please CC replies to me. Thanks, Mark _______________________________________________ https://lists.gnu.org/mailman/listinfo/libtool
